a = 3
b = 5

a, b = b, a
print(a, b)

# 逻辑
# 思维
a = a + b
b = a - b
a = a - b
print(a, b)

c = 7
d = 9

a, b, c, d  = d, c, b, a

print(a, b, c, d)
